Green’s Dictionary of Slang

1. an expert in a given field; usu. with at.

c.1580		‘I.T.’ Grim The Collier of Croydon I iv: I am an old dog at it.
1596		Nashe Have With You to Saffron-Walden in Works III (1883–4) 8: O, he hath been olde dogge at that drunken, staggering kinds of verse.
1664		S. Butler Hudibras Pt II canto 3 line 208: He had been long t’wards mathematicks, [...] Magick, horoscopy, astrology, / And was old dog at physiology.
1680		E. Hickeringill Reflections on Late Libel etc. 1: Take warning by Mr. Hickeringill’s Fate, and never dare to Print or Preach against Fantaicks; for they are old Dog at Lying and Slandering.
c.1698		B.E. Dict. Canting Crew n.p.: Old-dog-at-it, good or expert.
1725		New Canting Dict. [as cit. c.1698].
1731		C. Coffey Devil to Pay I ii: I’m an old Dog at that [...] I’m as great a master at Blind-Man’s-Buff as any in Europe.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Old dog at it, expert, accustomed.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1864, 1867, 1870		Hotten Sl. Dict. 191: old dog a knowing blade, an experienced person. [...] The Irish proverb says, ‘old dog for hard road,’ meaning that it requires an experienced person to execute a difficult undertaking.
1874		M. Clarke Term of His Natural Life (1897) 387: ‘The old dogs,’ as the experienced convicts are called.
1927		B. Cormack Racket Act III: ‘Old Dogs—,’ Miss Hayes!
1968		D. O’Grady A Bottle of Sandwiches 9: When it came to football he was good. He was an old dog at the game.
1999		Guardian Guide 28 Aug.–3 Sept. 32: These days, of course, we can see how the wise old dog put the lot of them to shame.

2. a man, usu. with overtones of admiration for his less than conventional lifestyle; also used fig. of an object and as a term of address.

1600		Shakespeare As You Like It I i: oli.: Get you with him, you old dog. adam.: Is ‘old dog’ my reward? Most true, I have lost my teeth in your service.
1608		Dekker Honest Whore Pt 2 (1630) V ii: Tho I cannot giue the old dog, my Father, a bone to gnaw, the Daughter shall bee sure of a Choke-peare .
1638		Earl Of Strafford Letters II (1739) 251: God bless the young Whelps, and for the old Dog there is less Matter .
1756		W. Toldervy Hist. of the Two Orphans IV 163: Did I not tell you, you old dog, said Copper, that my masters were men of fortune!
1785		Grose Classical Dict. of the Vulgar Tongue.
1848		Dickens Dombey and Son (1970) 188: An old campaigner, sir, said the Major, a smoke-dried, sun-burnt, used-up, invalided old dog of a Major, sir.
1857		C. Kingsley Two Years Ago xv: Decay be hanged! There’s life in the old dog yet, Sir!
1864, 1867, 1870		Hotten Sl. Dict.
1872		G.P. Burnham Memoirs of the US Secret Service 82: Bill Gurney is a wily old dog, however.
1883		H. Smart Hard Lines II 50: The apparition of a lady would have paralyzed the tongues of the gay old dogs.
1899		E.W. Hornung Amateur Cracksman (1992) 125: You deep old dog – of course I do!
1901		Boy’s Own Paper 2 Feb. 278: You are a rum old dog to go masquerading about in this fashion.
1917		E. Ferber ‘The Gay Old Dog’ One Basket [title].
1926		K.S. Prichard Working Bullocks 248: Umphelby’s had replied by taking down the saws, overhauling and replacing them, saying there was ‘a lot of life in the old dog yet’.
1930		W.S. Maugham Bread-Winner Act I: I don’t mind showing you young things that there’s life in the old dog yet.
1937		J. Curtis There Ain’t No Justice 132: Let’s have a bit of sport. There’s life in the old dog yet. I’m good for one three minute round.
1939		C. Himes ‘With Malice Toward None’ in Coll. Stories (1990) 53: What are you doing these days, Chick, old dog?
1950		S. Murphy Stone Mad (1966) 139: Oh, he was a proper old dog!
c.1951		N. Algren ‘Watch Out for Daddy’ in Entrapment (2009) 125: he may not be the best macker there is. But he is the meanest old dog of a Daddy in town.
1960		Wodehouse Jeeves in the Offing 94: There was so much life in the old dog still.
1970		H.E. Bates A Little of What You Fancy (1985) 510: The old dog, Pop thought.
1982		R. Dahl Revolting Rhymes n.p.: The mother cried, ‘By gad, I will! / There’s life within the old dog still!’.
1999		Indep. Information 3–9 July 57: There is still quite a bit of pizazz in the old dog.

3. (US, also the dog) constr. with the, syphilis [? the disease ‘bites’ the sufferer].

1935		A.J. Pollock Und. Speaks.
1950		Goldin et al. DAUL 60/1: Dog, n. [...] 4. A venereal disease, especially syphilis. ‘Getting a bite of the old dog (syphilis) started that kid on the heist (holdup). He had to pay croakers (doctors) that wouldn’t beef (report) to his people.’.
1962		Ragen & Finston World’s Toughest Prison 797: dog – syphillis [sic].